Fitment & front brake spec
| Spec | STOPFLEX front upgrade |
|---|---|
| Vehicle | Audi RS4 (B9) |
| Front caliper | Factory Akebono 6-piston fixed front caliper |
| Front rotor | STOPFLEX carbon ceramic rotor on model-specific hats |
| Front rotor size | 380 x 34 mm |
| Axle scope | Front CCB rotor upgrade |
| Pad pairing | STOPFLEX matched pad set for carbon ceramic use |
Confirm this first
This kit is built for the RS4 B9 still running the factory Akebono 6-piston fixed front calipers. It reuses those calipers and swaps the rotor, so if your car has a different front brake setup, check fitment before you order.
What the upgrade changes
| STOPFLEX feature | Why it matters on the RS4 B9 | What you notice |
|---|---|---|
| Carbon ceramic rotor, about half the weight of same-size steel | The B9 leans hard on its front axle. Lighter rotors cut unsprung mass right where the car works hardest. | Front end feels less heavy over rough pavement and quicker to settle in fast direction changes. |
| Heat tolerance that holds ~0.3u at 900°C | Repeated high-speed stops cook steel rotors and soften the pedal. Carbon ceramic shrugs off that heat. | Pedal stays consistent after a run of hard stops instead of going long and vague. |
| STOPFLEX pad pairing over 0.4u at normal temps | You want bite when the brakes are cold on the first stop, not just when they're hot. | Firmer, more linear pedal from the first press without being grabby in traffic. |
| Low dust, no-rust rotor face | RS4 wheels show dust fast, and steel rotors rust overnight after a wash or wet drive. | Cleaner wheels between washes and no orange film on the rotor faces. |
| Long-fiber CCB construction | A heavy, fast street car needs rotor strength and life, not just one good track session. | Street life can reach about 250,000 to 300,000 km when the car isn't tracked. |
What gets better
- Lower unsprung mass at both front corners
- More consistent pedal after repeated hard braking
- Sharper front-end response over uneven roads
- Very low brake dust with STOPFLEX pads
- Rotor faces that don't rust after rain or washing
- Normal cold bite even around -20°C on the first stop
What to confirm first
- Your car still has the factory Akebono 6-piston fixed front calipers
- The 380 x 34 mm front rotor matches your application
- You're running the STOPFLEX pad set made for carbon ceramic use
- This is a front-axle rotor upgrade, not a full big-brake conversion
If you're not sure your car matches the spec shown here, send us your VIN and current brake details and we'll confirm Audi RS4 B9 fitment before you order through our Audi CCB collection.
Build gallery
RS4 B9 CCB FAQ
Do I have to change the factory front calipers on my RS4 B9?
No. This is built for the RS4 B9 running the factory Akebono 6-piston fixed front calipers. The STOPFLEX rotors use model-specific hats, so it goes in as a rotor upgrade, not a full caliper conversion.
What will I actually feel on the street?
A cleaner, more consistent pedal, especially after a string of hard stops. With STOPFLEX pads, normal-temperature friction can run over 0.4μ, so response stays sharp without making the car a pain to drive every day.
Does it cut brake dust and stop rotor rust?
Yes. Paired with STOPFLEX pads, dust is very low next to a typical steel setup, and the carbon ceramic rotors don't rust after rain or a wash.
How long do these rotors last on the street?
On a street-driven car that never sees a track, rotor life can reach about 250,000 to 300,000 km. That's a big durability edge over steel for owners who actually rack up the miles.
What is the front rotor size for this RS4 B9 setup?
The front carbon ceramic rotors measure 380 x 34 mm and bolt to model-specific hats sized for the RS4 B9 with the factory Akebono 6-piston front caliper.
